I am between a rock and a hard place. I always used Sainsburys, but they changed the depot my stuff came from and the new delivery drivers went from nice to absolutely appalling bordering on abusive - man with a big grin watching woman with dislocated shoulder lug heavy shopping, creepy!
Tesco are rubbish here, though great for people I know in other areas. You can order what you like, state clearly no substitutions and beg, plead and cry, you cannot guarantee what will turn up. Or that it will actually make it into my garden. I always insist that they at least bring the shopping past my gate, and with the second lot of Sainsbury drivers that was not guaranteed and Tesco in the past have left it literally in the road - the bit where cars drive!
I have tried Ocado, and they are lovely, but apart from the cost they don't always have what I want, they don't have the range.
So I use Asda, keeping everything crossed that it doesn't completely wreck the bank account. I am always careful that there is a cushion, and will eke out food etc as much as possible if there is a doubt.
I have physical problems, I can't always get out and shop easily so I am desperately dependent on the grocery delivery. So currently Asda it is, and they are lovely! So far...